The vast majority of the elderly live in their own homes. These homes are often unsuitable for their current financial and physical capabilities due to size, expense, or structural and neighborhood characteristics. Despite the declining level of services provided by these homes, housing adjustment by moving is rare among the elderly, especially homeowners. This phenomenon has been called life-cycle lock-in. The proposed study will investigate hypothesized causes of lock-in, such as the elderly's attachment to their current social, spatial, and physical environment provided by the home and neighborhood, need for personal security and life continuity, ignorance of housing alternatives, lack of good housing alternatives, and high costs of moving. Hypothesized consequences of lock-in include enhanced threat of accident and crime, reduced consumption of medical services and food, inaccessibility to social, medical, and shopping facilities, and environmental stress. All adversely affect health and life satisfaction. Comprehensive data concerning the health, housing, mobility, life satisfaction, and economic situation of the elderly will be drawn from three existing national household surveys. An improved residential mobility model, which builds on contributions from economics, sociology, gerontology, and psychology, will be estimated by multivariate least squares and maximum likelihood regression techniques. Implications of this research for existing and envisioned public policies will be explored. These policies include property tax relief, utility cost relief, subsidized housing, income tax provisions, reverse annuity mortgages, and various social services.